1. Field of the Invention
The present invention relates to a perpendicular magnetic recording head for recording on a magnetic recording medium such as, for example, a disk having a rigid film by applying a perpendicular magnetic field. More specifically, the object of the present invention is to provide a perpendicular magnetic recording head compatible with high density recording by suppressing the occurrence of fringing of recording patterns, and a method for manufacturing the magnetic recording head.
2. Description of the Related Art
A device for high density recording of magnetic data on a recording medium such as a disk has utilized a perpendicular magnetic recording method. FIG. 41 is a cross-sectional view showing the general structure of a perpendicular magnetic recording head to be used in the perpendicular magnetic recording method described above.
The perpendicular magnetic recording head H used in the perpendicular magnetic recording method is provided at a trailing side end face 1a of a slider 1 that travels by floating or sliding on a recording medium. For example, the perpendicular magnetic recording head H is disposed between a non-magnetic film 2 and a non-magnetic coating film 3 at the trailing side end face 1a of the slider 1.
The perpendicular magnetic recording head H is composed of an auxiliary magnetic pole layer 4 made of a ferromagnetic material and a main magnetic pole layer 5, which is formed on the auxiliary magnetic pole layer 4, is separated therefrom by a space, and is made of the same ferromagnetic material, and an end face 4a of the auxiliary magnetic pole layer 4 and an end face 5a of the main magnetic pole layer 5 are exposed at an opposing face Ha opposing a recording medium Md. The auxiliary magnetic pole layer 4 and the main magnetic pole layer 5 are magnetically coupled with each other at a magnetic coupling part 6 located behind the opposing face Ha.
A non-magnetic insulation layer 7 made of an inorganic material such as Al2O3 or SiO2 is located between the auxiliary magnetic pole layer 4 and the main magnetic pole layer 5. An end face 7a of this non-magnetic insulation layer 7 is exposed at the opposing face Ha between the end face 4a of the auxiliary magnetic pole layer 4 and the end face 5a of the main magnetic pole layer 5.
Coil layers 8 made of a conductive material such as Cu are embedded in the non-magnetic insulation layer 7.
The thickness hw of the end face 5a of the main magnetic pole layer 5 is made to be smaller than the thickness hr of the end face 4a of the auxiliary magnetic pole layer 4, as shown in FIG. 41. The width of the end face 5a of the main magnetic pole layer 5 in the track width direction (the X-direction) corresponds to the track width, and this width is also made to be sufficiently smaller than the width of the end face 4a of the auxiliary magnetic pole layer 4 in the track width direction.
The recording medium Md for magnetic recording with the perpendicular magnetic recording head H moves in the Z-direction relative to the perpendicular magnetic recording head H, and a rigid film Ma and a soft film Mb are provided on the surface and inside of the recording medium, respectively.
A leakage recording magnetic field vertically passes through the rigid film Ma of the recording medium Md to the soft film Mb between the end face 4a of the auxiliary magnetic pole layer 4 and the end face 5a of the main magnetic pole layer 5 when a recording magnetic field is induced in the auxiliary magnetic pole layer 4 and main magnetic pole layer 5 by causing an electric current to flow in the coil layer 8. Since the area of the end face 5a of the main magnetic pole layer 5 is sufficiently narrower than the area of the end face 4a of the auxiliary magnetic pole layer 4, the magnetic flux φ converges on the portion opposed to the end face 5a of the main magnetic pole layer 5, thereby recording magnetic data on the rigid film Ma at the portion opposed to the end face 5a. 
FIG. 42 is a fragmentary front view of the perpendicular magnetic recording head shown in FIG. 41 viewed from the opposing face side opposing the recording medium. The main magnetic pole layer 5 of the perpendicular magnetic recording head shown in FIGS. 41 and 42 is plated on a plating underlayer 5b using a magnetic material. The main magnetic pole layer 5 formed by deposition has a curved convex surface 5c. The side faces 5d and 5d of the main magnetic pole layer 5 are perpendicular to the track width direction (the X-direction in the drawing) in the conventional perpendicular magnetic recording head.
FIG. 43 shows a plan view of a recording track on the recording medium on which signals are recorded by the perpendicular magnetic recording head shown in FIGS. 41 and 42.
A skew angle may be formed by allowing the side faces 5d of the main magnetic pole layer 5 to be inclined against the tangent of the rotational direction (Z-direction) of the recording medium Md when the slider 1 moves from the inner circumference to the outer circumference of the disk-shaped recording medium Md. If the side faces 5d of the main pole layer 5 are assumed to be perpendicular to the track width direction, as shown in FIG. 42, then the side faces 5d of the main magnetic pole layer impart an inclined magnetic field outside the track width Tw1, as shown by broken lines, to generate fringing F when the side faces 5d of the main magnetic pole layer 5 are inclined against the tangent of the direction of travel (the Z-direction) of the recording medium, thereby causing decrease in off-track performance.
The magnetic domain boundary B1 is curved when the surface 5c of the main magnetic pole layer 5 forms a curved convex face. As a result, the pulse width of the reproduced waveform is increased, and a clear distribution of the recording magnetic field cannot be obtained for high density recording. Consequently, it becomes difficult to improve the recording density in the longitudinal direction of the recording track (the A-direction in the drawing).